β-delayedγdecay ofP26: Possible evidence of a proton halo Academic Article uri icon

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abstract

  • Background: Measurements of $\beta$ decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies. Purpose: To measure the $\beta$-delayed $\gamma$ decay of $^{26}$P and compare the results with previous experimental results and shell-model calculations. Method: A $^{26}$P fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its $\beta$-delayed $\gamma$-ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background. Results: The absolute intensities of $^{26}$P $\beta$-delayed $\gamma$-rays were determined. A total of six new $\beta$-decay branches and 15 new $\gamma$-ray lines have been observed for the first time in $^{26}$P $\beta$-decay. A complete $\beta$-decay scheme was built for the allowed transitions to bound excited states of $^{26}$Si. $ft$ values and Gamow-Teller strengths were also determined for these transitions and compared with shell model calculations and the mirror $\beta$-decay of $^{26}$Na, revealing significant mirror asymmetries. Conclusions: A very good agreement with theoretical predictions based on the USDB shell model is observed. The significant mirror asymmetry observed for the transition to the first excited state ($\delta=51(10)\%$) may be evidence for a proton halo in $^{26}$P.

authors

  • Pérez-Loureiro, D
  • Wrede, C
  • Bennett, MB
  • Liddick, SN
  • Bowe, A
  • Brown, BA
  • Chen, Alan
  • Chipps, KA
  • Cooper, N
  • Irvine, D
  • McNeice, E
  • Montes, F
  • Naqvi, F
  • Ortez, R
  • Pain, SD
  • Pereira, J
  • Prokop, CJ
  • Quaglia, J
  • Quinn, SJ
  • Sakstrup, J
  • Santia, M
  • Schwartz, SB
  • Shanab, S
  • Simon, A
  • Spyrou, A
  • Thiagalingam, E

publication date

  • June 20, 2016